Physical inactivity Sample Clauses

Physical inactivity. The role of regulation of bone structure by physical activity has been shown to begin as early as 5 -7 weeks of prenatal life [94, 95]. Environmental influences during childhood and puberty have been shown to benefit bone mineral development. Physical activity in childhood stimulates the bone remodelling process and expands bone size to produce larger and stronger bones [96, 97]. Weight bearing exercise is believed to increase bone density by direct stimulation of the bone remodelling process, while a lack of weight bearing activity and immobilisation due to best rest, paraplegia and also during space flight is known to produce rapid bone loss in humans [98-100]. It has been reported that the initial bone loss as a result of immobilisation is approximately 1% per week and up to 4% of bone mass can be lost per month during initial phases of bed rest [11, 101]. Bone remineralisation begins again following the re-introduction of weight bearing exercise following long periods of inactivity, however this process is much slower and often incomplete [102]. Studies have shown the beneficial effect of weight bearing activity on bone [103-106] suggesting that weight bearing exercise is an important factor in the regulation and maintenance of bone mass.

Physical inactivity. The increasing urbanisation and mechanisation of the world has resulted in a reduction in the levels of physical activity. The WHO suggests that more than 60% of the global population is not sufficiently active [259] and approximately 3.2 million deaths each year are attributable to a sedentary lifestyle [260]. Research has shown that all individuals can benefit from regular physical activity, whether they participate in vigorous exercise or moderate health-enhancing exercise [261, 262]. Mobility and function can be improved even in the most frail and elderly adults [263]. Individuals who are physically more active have lower rates of all-cause mortality [264], most likely due to a decrease in chronic diseases, including coronary artery disease (CAD). This low rate may result from an improvement in CV risk factors, enhanced fibrinolysis, improved endothelial function, physical activity and reduced CV risk [264].